1. Field of the Invention
One embodiment of the present invention relates to a semiconductor device. For example, one embodiment of the present invention relates to a programmable logic device in which the structure of hardware can be changed and a semiconductor device including the programmable logic device.
2. Description of the Related Art
In a programmable logic device (PLD), a logic circuit is formed using adequate-scale programmable logic blocks (PLE), and the functions of the logic blocks and the connection between the logic blocks can be changed after manufacture. Specifically, the PLD includes a plurality of logic blocks and a routing resource for controlling the connection between the logic blocks. The functions of the logic blocks and the connection between the logic blocks formed using a routing resource are defined by configuration data, and the configuration data is stored in a register included in each logic block or a register included in the routing resource. A register for storing configuration data is hereinafter referred to as a configuration memory.
A PLD in which a logic circuit can be reconfigured during operation (this process is called dynamic reconfiguration) has an advantage of high area efficiency over a normal PLD. A multi-context method achieves dynamic reconfiguration by storing a plurality of groups of configuration data in a configuration memory. Compared with a configuration data transferring method that achieves dynamic reconfiguration by transferring configuration data from a memory element to a configuration memory in each group, the multi-context method can reconfigure a logic circuit at high speed.
Patent Document 1 discloses a programmable LSI in which a dynamic random access memory (DRAM) is used as a memory element and a static random access memory (SRAM) is used as a configuration memory.